As information is increasingly electronized, a technology for managing an enormous amount of information is attracting attention. For example, one of technologies for managing an enormous amount of information is a technology for extending performance or capacity of a storage. Specifically, there has been proposed a scale-out type storage which allocates one logical disk configured with a plurality of storages to a server. For example, as a technology relating to the scale-out type storage, Japanese Unexamined Patent Application Publication No. 2016-024679 discloses a technology for controlling an order of write access to a plurality of nodes and preventing occurrence of mismatching among mirror data.
Note that Japanese Unexamined Patent Application Publication No. 2004-280862 describes, as a technology for managing an enormous amount of information, a technology for connecting a disk array controller, disk devices, and a host by one interface in a system that implements redundant arrays of independent disks (RAID), thereby decreasing the number of interfaces among these devices and implementing low cost. Further, Japanese Unexamined Patent Application Publication No. 2003-085017 discloses a technology for storing copy data of a master disk in a remote disk. Further, Japanese Unexamined Patent Application Publication No. 2013-045379 discloses a technology for distributed arrangement of data into a plurality of storage nodes by using a technique of a key-value store (KVS).